Hello everyone! My name is Mike Howe and I’m the newest member of the Gratton Lab. I got my BA in Biology at Gustavus Adolphus College and my Master’s in Entomology at University of Wisconsin-Madison with Kenneth Raffa. I will be continuing my work in forest entomology in combination with both Claudio and Ken. In my free time, I ride my bike, work on my bouldering at the rock climbing gym, hit the (uphill) slopes cross-country skiing, and play pickup soccer.
Currently, I’m investigating how mountain pine beetle (Dendroctonus ponderosae) interacts with its historical host, lodgepole pine (Pinus contorta), and a semi-naive host, whitebark pine (Pinus albicaulis). My research questions are focused on how differences in host tree defensive chemistry affect mountain pine beetle attack behavior. I get to study everything from how bacterial associates of bark beetles affect successful colonization of trees to how landscape structure of whitebark pine and lodgepole pine affect probabilities of mountain pine beetle outbreak.
But enough about me!
I want to give a little background on my study system, whitebark pine. Whitebark pine is a high alpine keystone species that contributes to ecosystem stability, provides habitat for wildlife, and alters hydrological cycling by prolonging snowpack retention. Whitebark pine is often found in pockets as its seeds are dispersed by Clark’s nutcracker, which buries seeds in caches. Whitebark pine is also a very slow growing tree and is one of the only organisms that thrives in extreme alpine habitats. Unfortunately, in recent years, whitebark pine has been threatened by a nonnative fungus, white pine blister rust (Cronartium ribicola), mountain pine beetle, and warming temperatures. The combination of these risk factors has led the US Fish & Wildlife Service to consider whitebark pine as a candidate species for the endangered species list.
Our research on mountain pine beetle- whitebark pine interactions leads me to Oregon each summer to find both whitebark pine and lodgepole pine. Last summer, I collected needles and phloem (tissue right under the bark) of both tree species to analyze their defensive chemistry. I do this by placing the tree tissues in a solvent to extract the monoterpenes and then measure them using gas chromatography. Monoterpenes are common plant defensive compounds that are extremely fragrant. Monoterpene blends are responsible for the smells of pine trees (think Christmas tree), anis (black licorice), thyme, hops (thats where the citrus smell comes from), and of course, citrus. We are interested in how the different monoterpene blends in whitebark and lodgepole pine affect mountain pine beetles that are attempting to attack the trees.
Next summer I will be heading out to Oregon again and collecting more plant tissues for chemical analysis. The view from my field sites is amazing and I can’t wait to get back out there!